Magnetohydrodynamic Stagnation-point Flow and Heat Transfer over an Exponentially Stretching/Shrinking Sheet

摘要

This paper considers a numerical investigation on the steady laminar two-dimensional MHD stagnation-point flow and heat transfer of an incompressible viscous fluid impinging normal to an exponentially stretching/shrinking flat sheet in the presence of a non-uniform magnetic field applied in a direction normal to the flat sheet. The sheet surface temperature is assumed to also vary exponentially with the distance from the stagnation-point. The governing system of partial differential equations is first transformed into ordinary differential equations, and solved numerically using an implicit finite-difference scheme known as the Keller-box method. The effects of the stretching/shrinking parameter ε and the magnetic parameter on the flow field and heat transfer characteristics are discussed. It is found that the magnitude of the skin friction coefficient |f~n(o)|, and the local Nusselt number -θ'(0) increase with both the magnetic parameter M and the stretching/shrinking parameter ε. For the shrinking case, it is found that there is a minimum value ε_c of the shrinking parameter ε for which solution exists, and its value is dependent on the value of M, and dual solutions exist for some range of values of the shrinking parameter ε.